If a customer complains about the above error, this could be caused by contaminated engine coolant.
Such contamination (rust, metal particles from the cast-iron block) blocks the small openings in the heat exchanger preventing flow.
In this case, proceed as follows:
- Drain the coolant from the engine.
- Remove the thermostat housing, remove the thermostat and refit the housing.
- Fill the cooling system with fresh water and HELLA cleaning agent for cooling systems 8PE 351 225-841.
- Vent the cooling system.
- Warm up the engine. Set the heating to maximum and then let the engine idle for 10 minutes.
- Turn off the engine and leave it to cool.
- Drain the fluid from the system.
- Refill the system with clear water and vent the system.
- Warm up the engine.
Check heat output. If output has not improved, the heat exchanger must be replaced.
- Drain off the fluid again.
- Refit the thermostat. In such cases, it is recommended that the thermostat is also replaced.
- Fill the cooling system as per manufacturer’s instructions (correct coolant and correct mixing ratio).
Important safety note
Technical information and practical tips have been compiled by HELLA in order to provide professional support to vehicle workshops in their day-to-day work. The information provided on this website is intended for use by suitably qualified personnel only.
Reprinting, distribution, reproduction, exploitation in any form or disclosure of the contents of this document, even in part, is prohibited without our express, written approval and indication of the source. The schematic illustrations, pictures and descriptions serve only for the purposes of explanation and representation of the instructions and cannot be used as a basis for installation or assembly work. All rights reserved.
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